Percentile Calculator
Find the value below which a given percentage of observations in a group falls. Evaluates arbitrary percentiles (such as the 90th percentile for latency or 75th percentile for salaries) via linear interpolation.
List of numbers separated by commas, spaces, or tabs
Target percentile rank (e.g. 50 for median, 75 for 3rd quartile, 95 for top 5%)
Value at the specified rank position
How to Use This Calculator
- Enter your data values separated by commas or spaces.
- Specify the desired percentile rank (e.g. 75, 90, 95).
- View the interpolated percentile result alongside median and sample range.
Formula & Calculation Methodology
Calculates the fractional rank index and performs standard linear interpolation between adjacent ordered values (NIST / Excel method).
Worked Example
75th percentile of 15, 20, 35, 40, 50, 65, 70, 80, 90 (n = 9)
90th percentile of test scores
Frequently Asked Questions
How does the 50th percentile relate to the median?↓
The 50th percentile is mathematically identical to the statistical median, marking the point where half the data lies below and half above.
What is linear rank interpolation?↓
When the percentile index falls between two whole positions (e.g. 4.5), linear interpolation takes a weighted proportional average between the two surrounding data points.
What are quartiles?↓
Quartiles divide data into quarters: Q1 is the 25th percentile, Q2 is the 50th percentile (median), and Q3 is the 75th percentile.
What is a limitation of percentiles in small samples?↓
In very small samples (e.g. 4 items), computing high percentiles like the 99th percentile produces high estimation error and depends heavily on interpolation rules.
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Source Citation & Disclaimer
Informational tool only; not licensed tax, legal, or financial advice.